ath5k_dma.c

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/*
 * Copyright (c) 2004-2008 Reyk Floeter <reyk@openbsd.org>
 * Copyright (c) 2006-2008 Nick Kossifidis <mickflemm@gmail.com>
 *
 * Lightly modified for iPXE, July 2009, by Joshua Oreman <oremanj@rwcr.net>.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 */

FILE_LICENCE ( MIT );

/*************************************\
* DMA and interrupt masking functions *
\*************************************/

/*
 * dma.c - DMA and interrupt masking functions
 *
 * Here we setup descriptor pointers (rxdp/txdp) start/stop dma engine and
 * handle queue setup for 5210 chipset (rest are handled on qcu.c).
 * Also we setup interrupt mask register (IMR) and read the various iterrupt
 * status registers (ISR).
 *
 * TODO: Handle SISR on 5211+ and introduce a function to return the queue
 * number that resulted the interrupt.
 */

#include <unistd.h>

#include "ath5k.h"
#include "reg.h"
#include "base.h"

/*********\
* Receive *
\*********/

/**
 * ath5k_hw_start_rx_dma - Start DMA receive
 *
 * @ah: The &struct ath5k_hw
 */
void ath5k_hw_start_rx_dma(struct ath5k_hw *ah)
{
        ath5k_hw_reg_write(ah, AR5K_CR_RXE, AR5K_CR);
        ath5k_hw_reg_read(ah, AR5K_CR);
}

/**
 * ath5k_hw_stop_rx_dma - Stop DMA receive
 *
 * @ah: The &struct ath5k_hw
 */
int ath5k_hw_stop_rx_dma(struct ath5k_hw *ah)
{
        unsigned int i;

        ath5k_hw_reg_write(ah, AR5K_CR_RXD, AR5K_CR);

        /*
         * It may take some time to disable the DMA receive unit
         */
        for (i = 1000; i > 0 &&
                        (ath5k_hw_reg_read(ah, AR5K_CR) & AR5K_CR_RXE) != 0;
                        i--)
                udelay(10);

        return i ? 0 : -EBUSY;
}

/**
 * ath5k_hw_get_rxdp - Get RX Descriptor's address
 *
 * @ah: The &struct ath5k_hw
 *
 * XXX: Is RXDP read and clear ?
 */
u32 ath5k_hw_get_rxdp(struct ath5k_hw *ah)
{
        return ath5k_hw_reg_read(ah, AR5K_RXDP);
}

/**
 * ath5k_hw_set_rxdp - Set RX Descriptor's address
 *
 * @ah: The &struct ath5k_hw
 * @phys_addr: RX descriptor address
 *
 * XXX: Should we check if rx is enabled before setting rxdp ?
 */
void ath5k_hw_set_rxdp(struct ath5k_hw *ah, u32 phys_addr)
{
        ath5k_hw_reg_write(ah, phys_addr, AR5K_RXDP);
}


/**********\
* Transmit *
\**********/

/**
 * ath5k_hw_start_tx_dma - Start DMA transmit for a specific queue
 *
 * @ah: The &struct ath5k_hw
 * @queue: The hw queue number
 *
 * Start DMA transmit for a specific queue and since 5210 doesn't have
 * QCU/DCU, set up queue parameters for 5210 here based on queue type (one
 * queue for normal data and one queue for beacons). For queue setup
 * on newer chips check out qcu.c. Returns -EINVAL if queue number is out
 * of range or if queue is already disabled.
 *
 * NOTE: Must be called after setting up tx control descriptor for that
 * queue (see below).
 */
int ath5k_hw_start_tx_dma(struct ath5k_hw *ah, unsigned int queue)
{
        u32 tx_queue;

        /* Return if queue is declared inactive */
        if (ah->ah_txq.tqi_type == AR5K_TX_QUEUE_INACTIVE)
                return -EIO;

        if (ah->ah_version == AR5K_AR5210) {
                tx_queue = ath5k_hw_reg_read(ah, AR5K_CR);

                /* Assume always a data queue */
                tx_queue |= AR5K_CR_TXE0 & ~AR5K_CR_TXD0;

                /* Start queue */
                ath5k_hw_reg_write(ah, tx_queue, AR5K_CR);
                ath5k_hw_reg_read(ah, AR5K_CR);
        } else {
                /* Return if queue is disabled */
                if (AR5K_REG_READ_Q(ah, AR5K_QCU_TXD, queue))
                        return -EIO;

                /* Start queue */
                AR5K_REG_WRITE_Q(ah, AR5K_QCU_TXE, queue);
        }

        return 0;
}

/**
 * ath5k_hw_stop_tx_dma - Stop DMA transmit on a specific queue
 *
 * @ah: The &struct ath5k_hw
 * @queue: The hw queue number
 *
 * Stop DMA transmit on a specific hw queue and drain queue so we don't
 * have any pending frames. Returns -EBUSY if we still have pending frames,
 * -EINVAL if queue number is out of range.
 *
 */
int ath5k_hw_stop_tx_dma(struct ath5k_hw *ah, unsigned int queue)
{
        unsigned int i = 40;
        u32 tx_queue, pending;

        /* Return if queue is declared inactive */
        if (ah->ah_txq.tqi_type == AR5K_TX_QUEUE_INACTIVE)
                return -EIO;

        if (ah->ah_version == AR5K_AR5210) {
                tx_queue = ath5k_hw_reg_read(ah, AR5K_CR);

                /* Assume a data queue */
                tx_queue |= AR5K_CR_TXD0 & ~AR5K_CR_TXE0;

                /* Stop queue */
                ath5k_hw_reg_write(ah, tx_queue, AR5K_CR);
                ath5k_hw_reg_read(ah, AR5K_CR);
        } else {
                /*
                 * Schedule TX disable and wait until queue is empty
                 */
                AR5K_REG_WRITE_Q(ah, AR5K_QCU_TXD, queue);

                /*Check for pending frames*/
                do {
                        pending = ath5k_hw_reg_read(ah,
                                AR5K_QUEUE_STATUS(queue)) &
                                AR5K_QCU_STS_FRMPENDCNT;
                        udelay(100);
                } while (--i && pending);

                /* For 2413+ order PCU to drop packets using
                 * QUIET mechanism */
                if (ah->ah_mac_version >= (AR5K_SREV_AR2414 >> 4) && pending) {
                        /* Set periodicity and duration */
                        ath5k_hw_reg_write(ah,
                                AR5K_REG_SM(100, AR5K_QUIET_CTL2_QT_PER)|
                                AR5K_REG_SM(10, AR5K_QUIET_CTL2_QT_DUR),
                                AR5K_QUIET_CTL2);

                        /* Enable quiet period for current TSF */
                        ath5k_hw_reg_write(ah,
                                AR5K_QUIET_CTL1_QT_EN |
                                AR5K_REG_SM(ath5k_hw_reg_read(ah,
                                                AR5K_TSF_L32_5211) >> 10,
                                                AR5K_QUIET_CTL1_NEXT_QT_TSF),
                                AR5K_QUIET_CTL1);

                        /* Force channel idle high */
                        AR5K_REG_ENABLE_BITS(ah, AR5K_DIAG_SW_5211,
                                        AR5K_DIAG_SW_CHANEL_IDLE_HIGH);

                        /* Wait a while and disable mechanism */
                        udelay(200);
                        AR5K_REG_DISABLE_BITS(ah, AR5K_QUIET_CTL1,
                                                AR5K_QUIET_CTL1_QT_EN);

                        /* Re-check for pending frames */
                        i = 40;
                        do {
                                pending = ath5k_hw_reg_read(ah,
                                        AR5K_QUEUE_STATUS(queue)) &
                                        AR5K_QCU_STS_FRMPENDCNT;
                                udelay(100);
                        } while (--i && pending);

                        AR5K_REG_DISABLE_BITS(ah, AR5K_DIAG_SW_5211,
                                        AR5K_DIAG_SW_CHANEL_IDLE_HIGH);
                }

                /* Clear register */
                ath5k_hw_reg_write(ah, 0, AR5K_QCU_TXD);
                if (pending)
                        return -EBUSY;
        }

        /* TODO: Check for success on 5210 else return error */
        return 0;
}

/**
 * ath5k_hw_get_txdp - Get TX Descriptor's address for a specific queue
 *
 * @ah: The &struct ath5k_hw
 * @queue: The hw queue number
 *
 * Get TX descriptor's address for a specific queue. For 5210 we ignore
 * the queue number and use tx queue type since we only have 2 queues.
 * We use TXDP0 for normal data queue and TXDP1 for beacon queue.
 * For newer chips with QCU/DCU we just read the corresponding TXDP register.
 *
 * XXX: Is TXDP read and clear ?
 */
u32 ath5k_hw_get_txdp(struct ath5k_hw *ah, unsigned int queue)
{
        u16 tx_reg;

        /*
         * Get the transmit queue descriptor pointer from the selected queue
         */
        /*5210 doesn't have QCU*/
        if (ah->ah_version == AR5K_AR5210) {
                /* Assume a data queue */
                tx_reg = AR5K_NOQCU_TXDP0;
        } else {
                tx_reg = AR5K_QUEUE_TXDP(queue);
        }

        return ath5k_hw_reg_read(ah, tx_reg);
}

/**
 * ath5k_hw_set_txdp - Set TX Descriptor's address for a specific queue
 *
 * @ah: The &struct ath5k_hw
 * @queue: The hw queue number
 *
 * Set TX descriptor's address for a specific queue. For 5210 we ignore
 * the queue number and we use tx queue type since we only have 2 queues
 * so as above we use TXDP0 for normal data queue and TXDP1 for beacon queue.
 * For newer chips with QCU/DCU we just set the corresponding TXDP register.
 * Returns -EINVAL if queue type is invalid for 5210 and -EIO if queue is still
 * active.
 */
int ath5k_hw_set_txdp(struct ath5k_hw *ah, unsigned int queue, u32 phys_addr)
{
        u16 tx_reg;

        /*
         * Set the transmit queue descriptor pointer register by type
         * on 5210
         */
        if (ah->ah_version == AR5K_AR5210) {
                /* Assume a data queue */
                tx_reg = AR5K_NOQCU_TXDP0;
        } else {
                /*
                 * Set the transmit queue descriptor pointer for
                 * the selected queue on QCU for 5211+
                 * (this won't work if the queue is still active)
                 */
                if (AR5K_REG_READ_Q(ah, AR5K_QCU_TXE, queue))
                        return -EIO;

                tx_reg = AR5K_QUEUE_TXDP(queue);
        }

        /* Set descriptor pointer */
        ath5k_hw_reg_write(ah, phys_addr, tx_reg);

        return 0;
}

/**
 * ath5k_hw_update_tx_triglevel - Update tx trigger level
 *
 * @ah: The &struct ath5k_hw
 * @increase: Flag to force increase of trigger level
 *
 * This function increases/decreases the tx trigger level for the tx fifo
 * buffer (aka FIFO threshold) that is used to indicate when PCU flushes
 * the buffer and transmits it's data. Lowering this results sending small
 * frames more quickly but can lead to tx underruns, raising it a lot can
 * result other problems (i think bmiss is related). Right now we start with
 * the lowest possible (64Bytes) and if we get tx underrun we increase it using
 * the increase flag. Returns -EIO if we have have reached maximum/minimum.
 *
 * XXX: Link this with tx DMA size ?
 * XXX: Use it to save interrupts ?
 * TODO: Needs testing, i think it's related to bmiss...
 */
int ath5k_hw_update_tx_triglevel(struct ath5k_hw *ah, int increase)
{
        u32 trigger_level, imr;
        int ret = -EIO;

        /*
         * Disable interrupts by setting the mask
         */
        imr = ath5k_hw_set_imr(ah, ah->ah_imr & ~AR5K_INT_GLOBAL);

        trigger_level = AR5K_REG_MS(ath5k_hw_reg_read(ah, AR5K_TXCFG),
                        AR5K_TXCFG_TXFULL);

        if (!increase) {
                if (--trigger_level < AR5K_TUNE_MIN_TX_FIFO_THRES)
                        goto done;
        } else
                trigger_level +=
                        ((AR5K_TUNE_MAX_TX_FIFO_THRES - trigger_level) / 2);

        /*
         * Update trigger level on success
         */
        if (ah->ah_version == AR5K_AR5210)
                ath5k_hw_reg_write(ah, trigger_level, AR5K_TRIG_LVL);
        else
                AR5K_REG_WRITE_BITS(ah, AR5K_TXCFG,
                                AR5K_TXCFG_TXFULL, trigger_level);

        ret = 0;

done:
        /*
         * Restore interrupt mask
         */
        ath5k_hw_set_imr(ah, imr);

        return ret;
}

/*******************\
* Interrupt masking *
\*******************/

/**
 * ath5k_hw_is_intr_pending - Check if we have pending interrupts
 *
 * @ah: The &struct ath5k_hw
 *
 * Check if we have pending interrupts to process. Returns 1 if we
 * have pending interrupts and 0 if we haven't.
 */
int ath5k_hw_is_intr_pending(struct ath5k_hw *ah)
{
        return ath5k_hw_reg_read(ah, AR5K_INTPEND) == 1 ? 1 : 0;
}

/**
 * ath5k_hw_get_isr - Get interrupt status
 *
 * @ah: The @struct ath5k_hw
 * @interrupt_mask: Driver's interrupt mask used to filter out
 * interrupts in sw.
 *
 * This function is used inside our interrupt handler to determine the reason
 * for the interrupt by reading Primary Interrupt Status Register. Returns an
 * abstract interrupt status mask which is mostly ISR with some uncommon bits
 * being mapped on some standard non hw-specific positions
 * (check out &ath5k_int).
 *
 * NOTE: We use read-and-clear register, so after this function is called ISR
 * is zeroed.
 */
int ath5k_hw_get_isr(struct ath5k_hw *ah, enum ath5k_int *interrupt_mask)
{
        u32 data;

        /*
         * Read interrupt status from the Interrupt Status register
         * on 5210
         */
        if (ah->ah_version == AR5K_AR5210) {
                data = ath5k_hw_reg_read(ah, AR5K_ISR);
                if (data == AR5K_INT_NOCARD) {
                        *interrupt_mask = data;
                        return -ENODEV;
                }
        } else {
                /*
                 * Read interrupt status from Interrupt
                 * Status Register shadow copy (Read And Clear)
                 *
                 * Note: PISR/SISR Not available on 5210
                 */
                data = ath5k_hw_reg_read(ah, AR5K_RAC_PISR);
                if (data == AR5K_INT_NOCARD) {
                        *interrupt_mask = data;
                        return -ENODEV;
                }
        }

        /*
         * Get abstract interrupt mask (driver-compatible)
         */
        *interrupt_mask = (data & AR5K_INT_COMMON) & ah->ah_imr;

        if (ah->ah_version != AR5K_AR5210) {
                u32 sisr2 = ath5k_hw_reg_read(ah, AR5K_RAC_SISR2);

                /*HIU = Host Interface Unit (PCI etc)*/
                if (data & (AR5K_ISR_HIUERR))
                        *interrupt_mask |= AR5K_INT_FATAL;

                /*Beacon Not Ready*/
                if (data & (AR5K_ISR_BNR))
                        *interrupt_mask |= AR5K_INT_BNR;

                if (sisr2 & (AR5K_SISR2_SSERR | AR5K_SISR2_DPERR |
                             AR5K_SISR2_MCABT))
                        *interrupt_mask |= AR5K_INT_FATAL;

                if (data & AR5K_ISR_TIM)
                        *interrupt_mask |= AR5K_INT_TIM;

                if (data & AR5K_ISR_BCNMISC) {
                        if (sisr2 & AR5K_SISR2_TIM)
                                *interrupt_mask |= AR5K_INT_TIM;
                        if (sisr2 & AR5K_SISR2_DTIM)
                                *interrupt_mask |= AR5K_INT_DTIM;
                        if (sisr2 & AR5K_SISR2_DTIM_SYNC)
                                *interrupt_mask |= AR5K_INT_DTIM_SYNC;
                        if (sisr2 & AR5K_SISR2_BCN_TIMEOUT)
                                *interrupt_mask |= AR5K_INT_BCN_TIMEOUT;
                        if (sisr2 & AR5K_SISR2_CAB_TIMEOUT)
                                *interrupt_mask |= AR5K_INT_CAB_TIMEOUT;
                }

                if (data & AR5K_ISR_RXDOPPLER)
                        *interrupt_mask |= AR5K_INT_RX_DOPPLER;
                if (data & AR5K_ISR_QCBRORN) {
                        *interrupt_mask |= AR5K_INT_QCBRORN;
                        ah->ah_txq_isr |= AR5K_REG_MS(
                                        ath5k_hw_reg_read(ah, AR5K_RAC_SISR3),
                                        AR5K_SISR3_QCBRORN);
                }
                if (data & AR5K_ISR_QCBRURN) {
                        *interrupt_mask |= AR5K_INT_QCBRURN;
                        ah->ah_txq_isr |= AR5K_REG_MS(
                                        ath5k_hw_reg_read(ah, AR5K_RAC_SISR3),
                                        AR5K_SISR3_QCBRURN);
                }
                if (data & AR5K_ISR_QTRIG) {
                        *interrupt_mask |= AR5K_INT_QTRIG;
                        ah->ah_txq_isr |= AR5K_REG_MS(
                                        ath5k_hw_reg_read(ah, AR5K_RAC_SISR4),
                                        AR5K_SISR4_QTRIG);
                }

                if (data & AR5K_ISR_TXOK)
                        ah->ah_txq_isr |= AR5K_REG_MS(
                                        ath5k_hw_reg_read(ah, AR5K_RAC_SISR0),
                                        AR5K_SISR0_QCU_TXOK);

                if (data & AR5K_ISR_TXDESC)
                        ah->ah_txq_isr |= AR5K_REG_MS(
                                        ath5k_hw_reg_read(ah, AR5K_RAC_SISR0),
                                        AR5K_SISR0_QCU_TXDESC);

                if (data & AR5K_ISR_TXERR)
                        ah->ah_txq_isr |= AR5K_REG_MS(
                                        ath5k_hw_reg_read(ah, AR5K_RAC_SISR1),
                                        AR5K_SISR1_QCU_TXERR);

                if (data & AR5K_ISR_TXEOL)
                        ah->ah_txq_isr |= AR5K_REG_MS(
                                        ath5k_hw_reg_read(ah, AR5K_RAC_SISR1),
                                        AR5K_SISR1_QCU_TXEOL);

                if (data & AR5K_ISR_TXURN)
                        ah->ah_txq_isr |= AR5K_REG_MS(
                                        ath5k_hw_reg_read(ah, AR5K_RAC_SISR2),
                                        AR5K_SISR2_QCU_TXURN);
        } else {
                if (data & (AR5K_ISR_SSERR | AR5K_ISR_MCABT |
                            AR5K_ISR_HIUERR | AR5K_ISR_DPERR))
                        *interrupt_mask |= AR5K_INT_FATAL;

                /*
                 * XXX: BMISS interrupts may occur after association.
                 * I found this on 5210 code but it needs testing. If this is
                 * true we should disable them before assoc and re-enable them
                 * after a successful assoc + some jiffies.
                        interrupt_mask &= ~AR5K_INT_BMISS;
                 */
        }

        return 0;
}

/**
 * ath5k_hw_set_imr - Set interrupt mask
 *
 * @ah: The &struct ath5k_hw
 * @new_mask: The new interrupt mask to be set
 *
 * Set the interrupt mask in hw to save interrupts. We do that by mapping
 * ath5k_int bits to hw-specific bits to remove abstraction and writing
 * Interrupt Mask Register.
 */
enum ath5k_int ath5k_hw_set_imr(struct ath5k_hw *ah, enum ath5k_int new_mask)
{
        enum ath5k_int old_mask, int_mask;

        old_mask = ah->ah_imr;

        /*
         * Disable card interrupts to prevent any race conditions
         * (they will be re-enabled afterwards if AR5K_INT GLOBAL
         * is set again on the new mask).
         */
        if (old_mask & AR5K_INT_GLOBAL) {
                ath5k_hw_reg_write(ah, AR5K_IER_DISABLE, AR5K_IER);
                ath5k_hw_reg_read(ah, AR5K_IER);
        }

        /*
         * Add additional, chipset-dependent interrupt mask flags
         * and write them to the IMR (interrupt mask register).
         */
        int_mask = new_mask & AR5K_INT_COMMON;

        if (ah->ah_version != AR5K_AR5210) {
                /* Preserve per queue TXURN interrupt mask */
                u32 simr2 = ath5k_hw_reg_read(ah, AR5K_SIMR2)
                                & AR5K_SIMR2_QCU_TXURN;

                if (new_mask & AR5K_INT_FATAL) {
                        int_mask |= AR5K_IMR_HIUERR;
                        simr2 |= (AR5K_SIMR2_MCABT | AR5K_SIMR2_SSERR
                                | AR5K_SIMR2_DPERR);
                }

                /*Beacon Not Ready*/
                if (new_mask & AR5K_INT_BNR)
                        int_mask |= AR5K_INT_BNR;

                if (new_mask & AR5K_INT_TIM)
                        int_mask |= AR5K_IMR_TIM;

                if (new_mask & AR5K_INT_TIM)
                        simr2 |= AR5K_SISR2_TIM;
                if (new_mask & AR5K_INT_DTIM)
                        simr2 |= AR5K_SISR2_DTIM;
                if (new_mask & AR5K_INT_DTIM_SYNC)
                        simr2 |= AR5K_SISR2_DTIM_SYNC;
                if (new_mask & AR5K_INT_BCN_TIMEOUT)
                        simr2 |= AR5K_SISR2_BCN_TIMEOUT;
                if (new_mask & AR5K_INT_CAB_TIMEOUT)
                        simr2 |= AR5K_SISR2_CAB_TIMEOUT;

                if (new_mask & AR5K_INT_RX_DOPPLER)
                        int_mask |= AR5K_IMR_RXDOPPLER;

                /* Note: Per queue interrupt masks
                 * are set via reset_tx_queue (qcu.c) */
                ath5k_hw_reg_write(ah, int_mask, AR5K_PIMR);
                ath5k_hw_reg_write(ah, simr2, AR5K_SIMR2);

        } else {
                if (new_mask & AR5K_INT_FATAL)
                        int_mask |= (AR5K_IMR_SSERR | AR5K_IMR_MCABT
                                | AR5K_IMR_HIUERR | AR5K_IMR_DPERR);

                ath5k_hw_reg_write(ah, int_mask, AR5K_IMR);
        }

        /* If RXNOFRM interrupt is masked disable it
         * by setting AR5K_RXNOFRM to zero */
        if (!(new_mask & AR5K_INT_RXNOFRM))
                ath5k_hw_reg_write(ah, 0, AR5K_RXNOFRM);

        /* Store new interrupt mask */
        ah->ah_imr = new_mask;

        /* ..re-enable interrupts if AR5K_INT_GLOBAL is set */
        if (new_mask & AR5K_INT_GLOBAL) {
                ath5k_hw_reg_write(ah, ah->ah_ier, AR5K_IER);
                ath5k_hw_reg_read(ah, AR5K_IER);
        }

        return old_mask;
}